AD7822BNZ1 datasheet(19/28 Pages) AD

19 / 28 page

AD7822/AD7825/AD7829

Rev. C | Page 19 of 28

AD7822 STANDALONE OPERATION

The AD7822, being the single channel device, does not have any

multiplexer addressing associated with it and can be controlled

with just one signal, that is, the CONVST signal. As shown in

Figure 31, the RD and CS pins are both tied to the EOC pin.

The resulting signal can be used as an interrupt request signal

(IRQ) on a DSP, as a WR signal to memory, or as a CLK to a

latch or ASIC. The timing for this interface, as shown in Figure 31,

demonstrates how, with the CONVST signal alone, a conversion

can be initiated, data is latched out, and the operating mode of

the AD7822 can be selected.

AD7825/

AD7829

DB7 TO DB0

DB0 TO DB7

A15 TO A3

A2 TO A0

ADC I/O ADDRESS

MUX ADDRESS

A/D RESULT

MUX ADDRESS

(CHANNEL SELECTION A0 TO A2)

LATCHED

MICROPROCESSOR READ CYCLE

ADDRESS

DECODE

A15 TO A3

Figure 30. AD7825/AD7829 Simplified Microinterfacing Scheme

CONVST

EOC

DB7 TO DB0

AD7822

DSP/

LATCH/ASIC

CONVST

EOC

DB0 TO DB7

A/D RESULT

Figure 31. AD7822 Standalone Operation

AD7822BNZ1 Datasheet(PDF) 19 Page - Analog Devices